Comparative evaluation of amino acid composition and protein profile of gliadin from different extraction protocols

Abstract

AbstractSignificance and backgroundGliadin is known to trigger the celiac disease or gluten sensitivity affecting around 70 million people globally. Its detection in early stages has become a controversial issue due to lack of efficient gliadin extraction procedures. The efficiency of gliadin extraction procedure is therefore an important critical step to the results of detection of gluten‐derived products from either rapid immunoreactivity assay kit or analytical mass analysis. Hence, four gliadin extraction procedures were investigated using six wheat cultivars and analyzed for their physiochemical analysis.FindingsThe relative proportion of ω‐gliadin, α/β‐, γ‐gliadin, HMW‐NG, and amino acid concentration of gliadin varied with the extraction protocol. The higher proportion of α/β‐, γ‐gliadin was found in Weiss extraction protocol (79.74%–88.62%) and lowest in Wallace (50.70%–58.91%). The ω‐gliadin was found to be significantly (p ≤ .05) highest in DuPont (9.78%–22.54%) and lowest in Weiss protocol (0.46%–1.04%). The region between 36 and 44 kDa showed well‐resolved bands in DuPont, while a dense mass in other extraction protocols. Amino acid score was found to be significantly (p ≤ .05) higher in DuPont (79.53–91.75 g/100 g), followed by Osborne (67.17–81.16 g/100 g), Wallace (68.54–77.58 g/100 g), and Weiss (60.97–79.16 g/100 g) extracted gliadin.ConclusionThe extraction protocol was found to influence the proportion of different protein fractions as well as amino acid concentration.Significance and noveltyThe insight obtained gives a better understanding of how the same protein behaves when extracted with different extraction protocols.